Lucy and the Number Game

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Read problems statements in Russian here
Lucy had recently learned the game, called Natural Numbers.
The rules of the game are really simple. There are N players. At the same time, every player says one natural number. Let's call the number said by the ith player A_{i}. The person with the smallest unique number (that is, the smallest number that was not said by anybody else) wins. Sometimes, there is a case when there are no unique numbers at all. Then the game is obviously a draw, so nobody wins it.
Sometimes, it's hard to determine the winner, especially, when the number of players is enormous. So in this problem, your assignment will be: given the names of the players and the numbers every of them have said. Please, tell the name of the winner, or determine that nobody wins.
Input
The first line of the input contains an integer T denoting the number of test cases. The description of T test cases follows.
The first line of every test case consists of a single integer N  the number of players. Then, N lines will follow. Each of these N lines will consist of the player's name and the number A_{i} said by her, separated by a single space.
Output
For each test case, output a single line containing an answer to the corresponding test case  the name of the winner, or a string "Nobody wins.", if nobody wins the game.
Example
Input: 2 5 Kouta 1 Yuka 1 Mayu 3 Lucy 2 Nana 5 2 Lucy 2 Nana 2 Output: Lucy Nobody wins.
Scoring
Subtask 1 (17 points): T = 10000, 1 <= N <= 10, 1 <= A_{i} <= 10
Subtask 2 (19 points): T = 10000, 1 <= N <= 10, 1 <= A_{i} <= 2*10^{9}
Subtask 3 (30 points): T = 100, 1 <= N <= 1000, 1<= A_{i} <= 2*10^{9}
Subtask 4 (34 points): T = 10, 1 <= N <= 10000, 1 <= A_{i} <= 2*10^{9}
You can safely assume that in all the test cases the length of any name will not exceed five letters. All the players' names are unique.
Author:  xcwgf666 
Tester:  rubanenko 
Editorial  http://discuss.codechef.com/problems/NUMBERS 
Tags  cakewalk, ltime06, sorting, xcwgf666 
Date Added:  13102013 
Time Limit:  1 sec 
Source Limit:  50000 Bytes 
Languages:  C, CPP14, JAVA, PYTH, PYTH 3.5, CS2, PAS fpc, PAS gpc, RUBY, PHP, GO, NODEJS, HASK, SCALA, D, PERL, FORT, WSPC, ADA, CAML, ICK, BF, ASM, CLPS, PRLG, ICON, SCM qobi, PIKE, ST, NICE, LUA, BASH, NEM, LISP sbcl, LISP clisp, SCM guile, JS, ERL, TCL, PERL6, TEXT, CLOJ, FS 
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